The physical and mental state sometimes aquired by someone who consistently smokes, or used to smoke, a lot of weed. Typically characterized by the feeling and appearance of being stoned even when one is still technically sober.

See: Tommy Chong. The guy who works at your local smoke shop. Any stoner with a seemingly permanent smile and lazy eyes.

"Man, my dad hasn't smoked in years, but you can tell he's permastoned from his days on the commune".

The state of which an individual is not fully under the influence of marijuana, but is still feeling long lasting effects from the high. In this state, one is fully functional but does not feel normal and active. Being permastoned usually lasts until rest is acuired.